PRTG Manual: WMI Microsoft SQL Server 2014 Sensor

The WMI Microsoft SQL Server sensor monitors the performance of a Microsoft SQL Server via Windows Management Instrumentation (WMI). This sensor can monitor SQL General Statistics, Access Methods, the Buffer Manager, the Memory Manager, the Locks Manager, and SQL Statistics. The channels that are actually available for a sensor depend on the performance counters that you choose during setup.

Channel Overview

User Connections

Number of user connections. Because each user connection consumes some memory, configuring overly high numbers of user connections could affect throughput. Set user connections to the maximum expected number of concurrent users.

Logins

Total number of logins started per second.

Logouts

Total number of logout operations started per second.

Full Scans

Number of unrestricted full scans per second. These can be either base-table or full-index scans.

Page Splits

Number of page splits per second that occur as the result of overflowing index pages.

Table Lock Escalations

Number of times locks on a table were escalated.

Buffer Cache Hit Ratio

Percentage of pages found in the buffer cache without having to read from disk. The ratio is the total number of cache hits divided by the total number of cache lookups since an instance of SQL Server was started. After a long period of time, the ratio moves very little.

Because reading from the cache is much less expensive than reading from disk, you want this ratio to be high. Generally, you can increase the buffer cache hit ratio by increasing the amount of memory available to SQL Server.

Database Pages

Number of pages in the buffer pool with database content.

Stolen Pages

Number of pages used for miscellaneous server purposes (including procedure cache).

Page Life Expectancy

Number of seconds a page will stay in the buffer pool without references.

Connection Memory (KB)

Total amount of dynamic memory the server is using for maintaining connections.

Optimizer Memory (KB)

Total amount of dynamic memory the server is using for query optimization.

Total Server Memory (KB)

Total amount of dynamic memory (in kilobytes) that the server is using currently.

Target Server Memory (KB)

Total amount of dynamic memory the server can consume.

SQL Cache Memory (KB)

Total amount of dynamic memory the server is using for the dynamic SQL cache.

Lock Requests

Number of new locks and lock conversions per second requested from the lock manager.

Deadlocks

Number of lock requests per second that resulted in a deadlock.

Average Wait Time

Average amount of wait time (in milliseconds) for each lock request that resulted in a wait.

Batch Requests

Number of Transact-SQL command batches received per second. This statistic is affected by all constraints (such as I/O, number of users, cache size, complexity of requests, and so on). High batch requests mean good throughput.

SQL Compilations

Number of SQL compilations per second. Indicates the number of times the compile code path is entered. Includes compiles due to recompiles. After SQL Server user activity is stable, this value reaches a steady state.

SQL Re-Compilations

Number of SQL recompiles per second. Counts the number of times recompiles are triggered. In general, you want the recompiles to be low.

WMI Microsoft SQL Server Sensor

Remarks

This sensor can only be added to a device (computer) running a Microsoft SQL database.

Requires credentials for Windows systems to be defined for the device you want to use the sensor on.

WoW64 (Windows 32-bit on Windows 64-bit) must be installed on target systems that run Windows Server 2016.

Sensors using the Windows Management Instrumentation (WMI) protocol have high impact on the system performance! Try to stay below 200 WMI sensors per probe. Above this number, please consider using multiple Remote Probes for load balancing.

For a general introduction to the technology behind WMI, see manual section Monitoring via WMI.

You cannot add this sensor type to the Hosted Probe of a PRTG hosted by Paessler instance. If you want to use this sensor type, please add it to a remote probe device.

Add Sensor

The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the setting fields that are required for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change (nearly) all settings in the sensor's Settings tab later.

Select the instances of the Microsoft SQL Server you want to monitor. PRTG will create one sensor for each instance you choose in the Add Sensor dialog. The settings you choose will be valid for all sensors that you create when you finish this dialog.

The following settings for this sensor differ in the Add Sensor dialog in comparison to the sensor's Settings tab.

SQL Server Settings

MS SQL Server Instance

You see a list with the names of all items that are available to monitor. Add check marks in front of the respective lines to select the desired items. PRTG creates one sensor for each selection. You can also use the check box in the table head to select and deselect all items.

Display name and service name are provided as returned by the SQL Server.

SQL Server Version

Enter the version of the SQL Server. Usually, you can keep the default value.

SQL Counter Specific

SQL Performance Counters

You see a list of different groups of performance counters that the sensor can monitor for the instance(s) that you selected above. Every sensor that PRTG creates for the server instances monitors the performance counters you select here. Choose from:

General Statistics: Read general performance counters. This shows the number of user connections, and the number of logins and logouts per second.

Depending on your selection, PRTG creates a sensor with the specified channels.

To monitor more than one of the listed groups of performance counters, please add the sensor several times for the instance(s).

Sensor Settings

On the details page of a sensor, click the Settings tab to change its settings.

Usually, a sensor connects to the IP Address or DNS Name of the parent device where you created this sensor. See the Device Settings for details. For some sensor types, you can define the monitoring target explicitly in the sensor settings. See below for details on available settings.

Enter one or more Tags, separated by spaces or commas. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value.

You can add additional tags to the sensor if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags.

It is not possible to enter tags with a leading plus (+) or minus (-) sign, nor tags with round parentheses (()) or angle brackets (<>).

Priority

Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. Top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority).

SQL Server Settings

Service

Shows the service that this sensor monitors. Once a sensor is created, you cannot change this value. It is shown for reference purposes only. If you need to change this, please add the sensor anew.

Name

Shows the name of the server instance that this sensor monitors. Once a sensor is created, you cannot change this value. It is shown for reference purposes only. If you need to change this, please add the sensor anew.

WMI Class Name

Select whether PRTG automatically selects the name of the WMI class used for monitoring. Choose between:

This field is only visible if you enable manual WMI class selection above. This setting is intended for experienced users only. Enter the WMI class name that the sensor uses for monitoring your server instance.

Sensor Result

Define what PRTG will do with the sensor results. Choose between:

Discard sensor result: Do not store the sensor result.

Write sensor result to disk (Filename: Result of Sensor [ID].txt): Store the last result received from the sensor to the Logs (Sensors) directory in the PRTG data folder on the probe system the sensor is running on (on the Master node if in a cluster). File names: Result of Sensor [ID].txt and Result of Sensor [ID].Data.txt. This is for debugging purposes. PRTG overwrites these files with each scanning interval. For more information on how to find the folder used for storage, see section Data Storage.

This option is not available when the sensor runs on the Hosted Probe of a PRTG hosted by Paessler instance.

SQL Counter Specific

SQL Performance Counters

Shows the performance counter that this sensor monitors. Once a sensor is created, you cannot change this value. It is shown for reference purposes only. If you need to change this, please add the sensor anew.

Sensor Display

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel will always be displayed below the sensor's name. The available options depend on what channels are available for this sensor.

You can set another primary channel later by clicking the pin symbol of a channel in the sensor's Overview tab.

Graph Type

Define how different channels will be shown for this sensor.

Show channels independently (default): Show an own graph for each channel.

Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This will generate an easy-to-read graph that visualizes the different components of your total traffic. This option cannot be used in combination with manual Vertical Axis Scaling (available in the Sensor Channel Settings settings).

Stack Unit

This setting is only available if stacked graphs are selected above. Choose a unit from the list. All channels with this unit will be stacked on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.

Inherited Settings

By default, all following settings are inherited from objects higher in the hierarchy and should be changed there, if necessary. Often, best practice is to change them centrally in the Rootgroup's settings, see section Inheritance of Settings for more information. To change a setting only for this object, disable inheritance by clicking the button next to inherit from under the corresponding setting name. You will then see the options described below.

Select a scanning interval (seconds, minutes, or hours) from the list. The scanning interval determines the time the sensor waits between two scans. You can change the available intervals in the system administration on PRTG on premises installations.

If a Sensor Query Fails

Define the number of scanning intervals that a sensor has time to reach and check a device again in case a sensor query fails. The sensor can try to re-reach and check a device several times, depending on the option you select here, before it will be set to a Downstatus. This helps you avoid false alarms if the monitored device has only temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose between:

Set sensor to down immediately: The sensor will show an error immediately after the first failed request.

Set sensor to warning for 1 interval, then set to down (recommended): After the first failed request, the sensor will show a warning status. If the following request also fails, the sensor will show an error.

Set sensor to warning for 2 intervals, then set to down: Show an error status only after three consecutively failed requests.

Set sensor to warning for 3 intervals, then set to down: Show an error status only after four consecutively failed requests.

Set sensor to warning for 4 intervals, then set to down: Show an error status only after five consecutively failed requests.

Set sensor to warning for 5 intervals, then set to down: Show an error status only after six consecutively failed requests.

Sensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval until they show an error. It is not possible to set a WMI sensor to Down immediately, so the first option will not apply to these sensor types. All other options can apply.

If a sensor has defined error limits for channels, it will always show a Down status immediately, so no "wait" option will apply.

If a channel uses lookup values, it will always show a Down status immediately, so no "wait" options will apply.

Schedules, Dependencies, and Maintenance Window

Inheritance for schedules, dependencies, and maintenance windows cannot be interrupted. The corresponding settings from the parent objects will always be active. However, you can define additional settings here. They will be active at the same time as the parent objects' settings.

Schedule

Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) every week. With the period list option it is also possible to pause monitoring for a specific time span. You can create new schedules and edit existing ones in the account settings.

Schedules are generally inherited. New schedules will be added to existing ones, so all schedules are active at the same time.

Maintenance Window

Specify if you want to set up a one-time maintenance window. During a "maintenance window" period, this object and all child objects will not be monitored. They will be in a Paused status instead. Choose between:

Not set (monitor continuously): No maintenance window will be set and monitoring will always be active.

Set up a one-time maintenance window: Pause monitoring within a maintenance window. You can define a time span for a monitoring pause below and change it even for a currently running maintenance window.

To terminate a current maintenance window before the defined end date, change the time entry in Maintenance Ends field to a date in the past.

Maintenance Begins

This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the start date and time of the maintenance window.

Maintenance Ends

This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the end date and time of the maintenance window.

Dependency Type

Define a dependency type. Dependencies can be used to pause monitoring for an object depending on the status of another. You can choose between:

Use parent: Pause the current sensor if the device, where it is created on, is in Down status, or is paused by another dependency.

Select object: Pause the current sensor if the device, where it is created on, is in Down status, or is paused by another dependency. Additionally, pause the current sensor if a specific other object in the device tree is in Down status, or is paused by another dependency. Select below.

Master object for parent: Make this sensor the master object for its parent device. The sensor will influence the behavior of the device, where it is created on: If the sensor is in Down status, the device will be paused. For example, it is a good idea to make a Ping sensor the master object for its parent device to pause monitoring for all other sensors on the device in case the device cannot even be pinged. Additionally, the sensor will be paused if the parent group of its parent device is in Down status, or if it is paused by another dependency.

Testing your dependencies is easy! Simply choose Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later all dependent objects should be paused. You can check all dependencies in your PRTG installation by selecting Devices | Dependencies from the main menu bar.

Dependency

This field is only visible if the Select object option is enabled above. Click on the reading-glasses and use the object selector to choose an object on which the current sensor will depend.

Dependency Delay (Sec.)

Define a time span in seconds for a dependency delay. After the master object for this dependency goes back to Up status, PRTG will start monitoring the depending objects after this extra delayed. This can help to avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Please enter an integer value.

This setting is not available if you choose this sensor to Use parent or to be the Master object for parent. In this case, please define delays in the parent Device Settings or in the superior Group Settings.

Define which user group(s) will have access to the object you're editing. A table with user groups and types of access rights is shown. It contains all user groups from your setup. For each user group, you can choose from the following access rights:

Inherited: Use the access rights settings of the parent object.

None: Users in this group cannot see or edit the object. The object neither shows up in lists nor in the device tree. Exception: If a child object is visible to the user, the object is visible in the device tree, though not accessible.

Read: Users in this group can see the object and review its monitoring results.

Write: Users in this group can see the object, review its monitoring results, and edit the object's settings. They cannot edit access rights settings.

Full: Users in this group can see the object, review its monitoring results, edit the object's settings, and edit access rights settings.

You can create new user groups in the System Administration—User Groupssettings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option.

To change display settings, spike filter, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, see the Sensor Channel Settingssection.